Well, actually I already *had* an idea like that.  It goes like this:

What if by some magic accident Kasumi and Akane swap personalities?
*Not* their minds, mind you, just their behavior patterns.  All their
memories and feelings for others are intact, they just react to their
surrounding like the other one would normally have, i.e.
Kasumi flies off the handle and mallets people a lot, while Akane reacts
to Ranma's insults by saying "That was not a very nice thing to say,
Ranma." and looking sad.

<snip!>
What about it?  Do you think it's workable?
<<<<<<<<<<<<<<<

Sounds pretty interesting, though the Freaky Friday concept might work
too.  Go for it (unless you've got an even better idea stashed away
somewhere)!

tom